M55x0.75 male to M52x1 female thread adapter, adjustable

• Front side - M52x1 female thread
• Rear side - M55x0.75 male thread

Machined from high quality aluminium alloyWhy aluminium?.

This adapter is purposed to adjust relative position of two H-alpha filters for solar observations.

Rotating ("clocking") seems to have a few benefits:

• it provides freedom in repositioning (rotating) the multiple secondary reflections that's caused by the two H-alpha filters;
• it seems that at some positions, the solar disk appears brighter, although this is objectively difficult to tell without actually measuring, say with my astro camera (ZWO ASI174MM Pro). Rotating the most external filter causes some jitter and sag which in themselves affects brightness slightly.
• manipulating the "sweet spot" (Jacquinot spot). Tilted h-alpha filters can cause banding and reduce the sweet spot of maximum contrast.